Often, in various industries, a tacky material which tends to stick to other substances with which it comes in contact will be mixed with a powder or fibrous material to create a composite material having various uses and properties that are enhanced in comparison to either the tacky material or the powder material, alone. For example, asphalt used in asphaltic mixtures for use in paving, road surfacing, roofing, etc., is often mixed with granular or fine powder, such as limestone, to enhance or change the properties of the asphalt material. For example, fine powdered limestone may be added to asphalt to increase stability when used to cover shingles for roofing. Further, limestone, fine aggregates, and cellulosic or mineral fibers may be added to asphalt to increase its sealing properties for filling in cracks in construction or road surfacing. The addition of such powder or fibers allows asphalt to still have its securing properties, while permitting the asphalt to be handled and manipulated more easily to provide more accurate and stable sealing. Further, the addition of fine aggregate, limestone, cellulosic fibers, or mineral fibers also can help create asphaltic mixtures for paving and road surfacing that have improved strength and durability.
The transport of such asphalt to be used as binder in the various asphaltic mixture applications can be problematic. Typically, asphalt is handled in bulk form due to the fact that the material tends to stick together even after separation when stored in the same container. During processing in anticipation for use, the asphalt must be kept heated at over 275° F. in liquid form for subsequent handling and mixing. For example, asphalt binder is handled as a hot liquid from its origination point, usually the refinery, with heated rail cars or trucks. The asphalt binder remains heated in its liquefied state through shipment to and use in the asphalt mix plant. Since such material must be maintained at elevated temperatures for transfer to storage tanks and any transfer from one container to another until ultimate use, significant amounts of energy in the form of heat must be expended in order to maintain the asphalt in its liquefied state. It is estimated that, in the United States alone, over 60 billion pounds of asphalt must be kept continuously heated. Depending on any additives or other materials added to the asphalt, maintaining the asphalt at elevated temperatures for prolonged periods can adversely affect the properties of the asphalt.
Different techniques have been implemented in an attempt to improve the handling properties of tacky, deformable materials, such as asphalt, to allow more flexibility in its use and decrease the exorbitant amount of energy expended to keep such materials at the necessary elevated temperatures. For example, U.S. Pat. No. 5,254,385 to Hazlett discloses encapsulating asphalt with polymer capsules so that the encapsulated asphalt may be handled at ambient temperatures without the asphalt coagulating or coalescing together to make the asphalt unwieldy for use in various situations. However, the asphalt within the polymer capsules is still deformable and can be easily deformed under even slight pressure. Thus, if the polymer encapsulated asphalt is stored in conventional shippable containers having a height of, for example, two to three feet or more, the weight of the asphalt-filled capsules creates a pressure on the internal capsules. Under this pressure, the soft and malleable asphalt will deform within each capsule such that the capsules may interlock, thus preventing free flowing of the asphalt from the container. Also, the polymer covers may easily be compromised by cracks and fractures within the capsule walls. Thereafter, the individual capsules will start to adhere to one another. The adhering of large amounts of the asphalt-filled capsules makes them hard to manipulate in producing small batches of asphaltic mixture. In extreme cases, the capsules of asphalt may fracture and burst allowing the asphalt to coalesce together further complicating small batch uses. Additionally, the plastic covers used to encapsulate the asphalt may prevent the asphalt from properly adhering to the aggregate when melted.
U.S. Pat. No. 3,783,000 discloses a granular or flaky asphalt material that can be blended with limestone or other fine aggregate material to create a fully blended composite asphalt that can be manipulated and handled by adding pressure between rollers. However, the composite material must be broken off and then crushed into the specified amounts within batch applications. Such composite material is not flowable and cannot be easily metered for use in specified amounts for either large or small batch applications. Also, storage of this material in large containers can cause agglomeration due to interlocking of particles.